points are $\mathrm{A}\left(\frac{-8}{5}, 2\right)$ and $\mathrm{B}\left(\frac{2}{5}, 2\right)$

=>  $\left(x_{1}=\frac{-8}{5}, y_{1}=2\right)$ and $\left(x_{2}=\frac{2}{5}, y_{2}=2\right)$

$
\begin{aligned}
&\text { AB }=\sqrt{\left(\mathrm{x}_{2}-\mathrm{x}_{1}\right)^{2}+\left(\mathrm{y}_{2}-\mathrm{y}_{1}\right)^{2}} \\
&=\sqrt{\left\{\frac{2}{5}-\left(\frac{-8}{5}\right)\right\}^{2}+(2-2)^{2}} \\
&=\sqrt{(2)^{2}+(0)^{2}} \\
&=\sqrt{4+0} \\
&=\sqrt{4}
\end{aligned}
$

$=2$ units.